americans are now eligible for booster shots after the cdc gave the green light thursday night to moderna and j&j boosters. and backed the mixing and matching of the vaccines on the "today" show earlier, cdc director have rochelle walensky backed that mixing and matching. >> the vast majority of people will probably select the original one and did well with. but if you go into a pharmacy, and they don't have the one you that originally got it's okay to get the vaccine. >> joining me now a senior scholar at the johns hopkins school and boomer agency of school of health. can you explain -- it's different for moderna and j&j. >> for moderna and pfizer, everybody over the age of 65, six months from their second